RNA-directed RNA polymerase L (Respiratory syncytial virus) (RSV L protein)

RNA-directed RNA polymerase L (RSV L protein) is the large catalytic subunit of the respiratory syncytial virus (RSV) polymerase complex, essential for viral genome replication, transcription, and processing of viral mRNA. The protein (~250 kDa) comprises multiple functional domains: an RNA-dependent RNA polymerase (RdRp), a capping (PRNTase) domain, and a methyltransferase domain, which together orchestrate RNA synthesis, mRNA capping, methylation, and polyadenylation. RSV L associates with a tetrameric phosphoprotein (P) for full activity, forming a dynamic, multi-protein complex that precisely regulates initiation, elongation, and processing of RSV RNAs. Mutations in L are linked to resistance against polymerase inhibitors, making it a central focus for antiviral drug discovery against RSV infections

Other names

Large protein (L protein)RNA polymerase LRSV L polymerase

Inhibition of RNA-dependent RNA polymerization (blocks viral replication/transcription) Inhibition of capping/methylation enzymatic activities Allosteric inhibition or escape (some drugs induce mutations in L to escape inhibition)